Lower-body work capacity and one-repetition maximum squat prediction in college football players

The purpose of this study was to assess lower-body muscular strength and work capacity after off-season resistance training and the efficacy of predicting maximal squat strength (1 repetition maximum [1RM]) from repetitions to fatigue. National Collegiate Athletic Association Division-II football players (n = 58) were divided into low-strength (LS, 1RM < 365 lb, n = 32) and high-strength (HS, 1RM ≥ 365 lb, n = 26) groups before training based on median 1RM squat performance. Maximal repetitions to failure (RTFs) were performed with a relative load of 70% of 1RM before training and 60, 70, 80, and 90% of 1RM after 12 weeks of a linear periodization resistance training program. As a team, 1RM squat (32 ± 27 lb), 70% RTF (4.5 ± 4.5 reps), and work capacity at 70% 1RM load (1,482 ± 1,181 lb reps) increased significantly after training. Likewise, training resulted in significant increases in 1RM, RTF at 70% 1RM, and work capacity (load × reps) in both LS (8 ± 33 lb, 3.9 ± 4.7 reps, 1,736 ± 1,521 lb reps, respectively) and HS (27 ± 21 lb, 4.9 ± 4.4 reps, 2,387 ± 1,767 lb reps, respectively), with no significant difference between groups. There was no relationship between the change in work capacity and the change in muscular strength for either the LS (r = 0.02) or HS (r = 0.06) group. Predicted 1RMs were best when RTFs were performed using 80% 1RM (5-17 RTFs), with an error of ±5% in 95% of the subjects. In conclusion, the changes in muscular strength associated with an off-season training program appear to have a positive influence on squat work capacity at 70% of 1RM and allow favorable prediction of 1RM using submaximal loads.     

Short-term effects of strength and plyometric training on sprint and jump performance in professional soccer players

The purpose of this study was to compare the effects of combined strength and plyometric training with strength training alone on power-related measurements in professional soccer players. Subjects in the intervention team were randomly divided into 2 groups. Group ST (n = 6) performed heavy strength training twice a week for 7 weeks in addition to 6 to 8 soccer sessions a week. Group ST+P (n = 8) performed a plyometric training program in addition to the same training as the ST group. The control group (n = 7) performed 6 to 8 soccer sessions a week. Pretests and posttests were 1 repetition maximum (1RM) half squat, countermovement jump (CMJ), squat jump (SJ), 4-bounce test (4BT), peak power in half squat with 20 kg, 35 kg, and 50 kg (PP20, PP35, and PP50, respectively), sprint acceleration, peak sprint velocity, and total time on 40-m sprint. There were no significant differences between the ST+P group and ST group. Thus, the groups were pooled into 1 intervention group. The intervention group significantly improved in all measurements except CMJ, while the control group showed significant improvements only in PP20. There was a significant difference in relative improvement between the intervention group and control group in 1RM half squat, 4BT, and SJ. However, a significant difference between groups was not observed in PP20, PP35, sprint acceleration, peak sprinting velocity, and total time on 40-m sprint. The results suggest that there are no significant performance-enhancing effects of combining strength and plyometric training in professional soccer players concurrently performing 6 to 8 soccer sessions a week compared to strength training alone. However, heavy strength training leads to significant gains in strength and power-related measurements in professional soccer players.     

Comparison of Olympic vs. traditional power lifting training programs in football players

Twenty members of an National Collegiate Athletic Association Division III collegiate football team were assigned to either an Olympic lifting (OL) group or power lifting (PL) group. Each group was matched by position and trained 4-days.wk(-1) for 15 weeks. Testing consisted of field tests to evaluate strength (1RM squat and bench press), 40-yard sprint, agility, vertical jump height (VJ), and vertical jump power (VJP). No significant pre- to posttraining differences were observed in 1RM bench press, 40-yard sprint, agility, VJ or in VJP in either group. Significant improvements were seen in 1RM squat in both the OL and PL groups. After log10-transformation, OL were observed to have a significantly greater improvement in Delta VJ than PL. Despite an 18% greater improvement in 1RM squat (p > 0.05), and a twofold greater improvement (p > 0.05) in 40-yard sprint time by OL, no further significant group differences were seen. Results suggest that OL can provide a significant advantage over PL in vertical jump performance changes.     

The effects of carbohydrate loading on repetitive jump squat power performance

The beneficial role of carbohydrate (CHO) supplementation in endurance exercise is well documented. However, only few data are available on the effects of CHO loading on resistance exercise performance. Because of the repetitive use of high-threshold motor units, it was hypothesized that the power output (power-endurance) of multiple sets of jump squats would be enhanced following a high-CHO (6.5 g CHO kg body mass(-1)) diet compared to a moderate-CHO (4.4 g CHO kg body mass(-1)) diet. Eight healthy men (mean +/- SD: age 26.3 +/- 2.6 years; weight 73.0 +/- 6.3 kg; body fat 13.4 +/- 5.0%; height 178.2 +/- 6.1 cm) participated in 2 randomly assigned counterbalanced supplementation periods of 4 days after having their free-living habitual diet monitored. The resistance exercise test consisted of 4 sets of 12 repetitions of maximal-effort jump squats using a Plyometric Power System unit and a load of 30% of 1 repetition maximum (1RM). A 2-minute rest period was used between sets. Immediately before and after the exercise test, a blood sample was obtained to determine the serum glucose and blood lactate concentrations. No significant difference in power performance existed between the 2 diets. As expected, there was a significant (p 相似文献   

Comparison of weighted jump squat training with and without eccentric braking

The purpose of this study was to investigate the effect of weighted jump squat training with and without eccentric braking. Twenty male subjects were divided into two groups (n = 10 per group), Non-Braking Group and Braking Group. The subjects were physically active, but not highly trained. The program for Non-Braking Group consisted of 6 sets of 6 repetitions of weighted jump squats without reduction of eccentric load for 8 weeks. The training program for the Braking Group consisted of the same sets and repetitions, but eccentric load was reduced by using an electromagnetic braking mechanism. Jump and reach, countermovement jump, static jump, drop jump, one repetition maximum half squat, weighted jump squat, and isometric/isokinetic knee extension/flexion at several different positions/angular velocities were tested pre- and posttraining intervention. The Non-Braking Group exhibited greater improvement in peak torque during isokinetic concentric knee flexion at 300 degrees/s [Non-Braking Group: (mean +/- SD) 124.0 +/- 22.6 Nm at pre- and 134.1 +/- 18.4 Nm at posttraining, and Braking Group: 118.5 +/- 32.7 Nm at pre- and 113.2 +/- 26.7 Nm at posttraining]. Braking Group exhibited superior adaptations in peak power relative to body mass during weighted jump squat [Non-Braking Group: (mean +/- SD) 49.1 +/- 8.6 W/kg at pre- and 50.9 +/- 6.2 W/kg at posttraining, and Braking Group: 47.9 +/- 6.9 W/kg at pre- and 53.7 +/- 7.3 W/kg at posttraining]. It appears that power output in relatively slow movement (weighted jump squat) was improved more in the Braking Group, however strength in high velocity movements (isokinetic knee flexion at 300 degrees/s) was improved more in Non-Braking Group. This study supports load and velocity specific effects of weighted jump squat training.     

Relationship between sprint times and the strength/power outputs of a machine squat jump

Strength testing is often used with team-sport athletes, but some measures of strength may have limited prognostic/diagnostic value in terms of the physical demands of the sport. The purpose of this study was to investigate relationships between sprint ability and the kinetic and kinematic outputs of a machine squat jump. Thirty elite level rugby union and league athletes with an extensive resistance-training background performed bilateral concentric-only machine squat jumps across loads of 20% to 90% 1 repetition maximum (1RM), and sprints over 10 meters and 30 or 40 meters. The magnitudes of the relationships were interpreted using Pearson correlation coefficients, which had uncertainty (90% confidence limits) of approximately +/-0.3. Correlations of 10-meter sprint time with kinetic and kinematic variables (force, velocity, power, and impulse) were generally positive and of moderate to strong magnitude (r = 0.32-0.53). The only negative correlations observed were for work, although the magnitude was small (r = -0.18 to -0.26). The correlations for 30- or 40-meter sprint times were similar to those for 10-meter times, although the correlation with work was positive and moderate (r = 0.35-0.40). Correlations of 10-meter time with kinetic variables expressed relative to body mass were generally positive and of trivial to small magnitude (r = 0.01-0.29), with the exceptions of work (r = -0.31 to -0.34), and impulse (r = -0.34 to -0.39). Similar correlations were observed for 30- and 40-meter times with kinetic measures expressed relative to body mass. Although correlations do not imply cause and effect, the preoccupation with maximizing power output in this particular resistance exercise to improve sprint ability appears problematic. Work and impulse are potentially important strength qualities to develop in the pursuit of improved sprinting performance.     

Occlusion training increases muscular strength in division IA football players

The purpose of this study was to investigate the effectiveness of 4 weeks of low-intensity resistance training with blood-flow occlusion on upper and lower body muscular hypertrophy and muscular strength in National Collegiate Athletic Association Division IA football players. There were 32 subjects (average age 19.2 ± 1.8 years) who were randomized to an occlusion group or control group. The athletes performed 4 sets of bench press and squat in the following manner with or without occlusion: 30 repetitions of 20% predetermined 1 repetition maximum (1RM), followed by 3 sets of 20 repetitions at 20% 1RM. Each set was separated by 45 seconds. The training duration was 3 times per week, after the completion of regular off-season strength training. Data collected included health history, resting blood pressure, pretraining and posttraining bench press and squat 1RM, upper and lower chest girths, upper and lower arm girths, thigh girth, height, and body mass. The increases in bench press and squat 1RM (7.0 and 8.0%, respectively), upper and lower chest girths (3 and 3%, respectively), and left upper arm girth were significantly greater in the experiment group (p < 0.05). Occlusion training could provide additional benefits to traditional strength training to improve muscular hypertrophy and muscular strength in collegiate athletes.     

Comparison of the backward overhead medicine ball throw to power production in college football players

The purpose of this study was to determine the relationship of the backward overhead medicine ball (BOMB) throw to power production in college football players. Forty National Collegiate Athletic Association Division II college football players were studied at the end of an 8-week off-season conditioning program for power output determined from a countermovement vertical jump on a force plate and for maximal distance in the standing BOMB throw. Although the reliability of the BOMB test was high (interclass correlation coefficient = 0.86), there was a significant learning effect across 3 trials (p < 0.01). Peak and average powers generated during the vertical jump correlated moderately but significantly with the best BOMB throw distance (r = 0.59 and 0.63, respectively). Considering power relative to body mass or lean body mass failed to produce significant correlations with BOMB throw distance (r = 0.27 and 0.28, respectively). Therefore, the BOMB throw may have limited potential as a predictor of total body explosive power in college football players.     

Equipment and running surface alter sprint performance of college football players

The purpose of this study was to determine the effect of football equipment and running surface on sprint performance in NCAA Division II football players (n = 68). Players were timed in the 40-yd sprint on an indoor rubberized track (Day 1) and on an outdoor, natural-grass football field (Day 2) wearing either regulation football equipment or shorts and a T-shirt. Each player was assigned randomly to perform 2 trials under each condition on each surface, and the average of the 2 trials was used for analysis. Offensive backs, defensive backs, and linebackers were significantly faster than were offensive and defensive linemen in all trials, and subjects were collapsed into 2 groups, backs and linemen. Football equipment significantly impaired performance on the track (-2.8% +/- 1.7%) and the field (-2.9% +/- 1.8%). The increase in body mass due to the football equipment was significantly greater for backs (7.2% +/- 0.7%) than for linemen (6.5% +/- 1.0%), but produced a significantly greater impairment in sprint performance in linemen (-3.3% +/- 1.1%) as compared with backs (-2.5% +/- 1.5%). Sprint performance was significantly and equivalently impaired when running on grass (backs: -2.5 +/- 1.1%; linemen: -2.8 +/- 1.4%) as compared with the track. Thus, running a 40-yd sprint in football equipment on a natural grass field impairs performance by an average of 5.5% (+/- 2.3%) compared with running indoors with minimal apparel. Football equipment and running surface significantly impair sprint performance in college football players, the effect being greater in linemen than in backs, and is likely related to differences in muscle strength/power and body fat.     

Relative importance of strength, power, and anthropometric measures to jump performance of elite volleyball players

The purpose of this investigation was to examine the potential strength, power, and anthropometric contributors to vertical jump performances that are considered specific to volleyball success: the spike jump (SPJ) and counter-movement vertical jump (CMVJ). To assess the relationship among strength, power, and anthropometric variables with CMVJ and SPJ, a correlation and regression analysis was performed. In addition, a comparison of strength, power, and anthropometric differences between the seven best subjects and the seven worst athletes on the CMVJ test and SPJ test was performed. When expressed as body mass relative measures, moderate correlations (0.53-0.65; p < or = 0.01) were observed between the 1RM measures and both relative CMVJ and relative SPJ. Very strong correlations were observed between relative (absolute height-standing reach height) depth jump performance and relative SPJ (0.85; p < or = 0.01) and relative CMVJ (0.93; p 相似文献   

Comparison between linear and nonlinear in-season training programs in freshman football players

The purpose of this study was to compare linear (LT) with nonlinear (NL) in-season training programs in freshman football players during the course of 2 separate seasons. During the first year (n = 14, mean +/- SD = 177.3 +/- 4.8 cm, 88.0 +/- 9.7 kg), the LT program was employed 2 days per week. In the second year (n = 14, 175.0 +/- 7.1 cm, 94.2 +/- 20.5 kg), a 2 days per week LT was used. Subjects were tested for maximal strength in the squat (1 repetition maximum [1RM]) and bench press (1RM) exercises. A significant improvement in 1RM squat was seen in LT, but not in NL. No significant improvement in 1RM bench press was seen in either group. A significant difference between LT and NL was observed in Delta1RM squat (13.8 +/- 7.4 kg compared with 1.6 +/- 2.6 kg, respectively). Results of this study suggest that LT may be more effective in eliciting strength gains than NL in freshman football players during an in-season training program.     

Physical characteristics that predict functional performance in Division I college football players

Strength and conditioning professionals who work with collegiate football players focus much of their time and effort on developing programs to enhance athletic performance. Although there has been much speculation, there is little scientific evidence to suggest which combination of physical characteristics best predicts athletic performance in this population. The purpose of this investigation was to examine the relationship among 6 physical characteristics and 3 functional measures in college football players. Data were gathered on 46 NCAA Division I college football players. The 3 response variables were 36.6-m sprint, 18.3-m shuttle run, and vertical jump. The 6 regressor variables were height, weight, percentage of body fat, hamstring length, bench press, and hang clean. A stepwise multiple regression analysis was performed to screen for variables that predict physical performance. Regression analysis revealed clear prediction models for the 36.6-m sprint and 18.3-m shuttle run. The results of this investigation will help strength and conditioning specialists better understand the variables that predict athletic performance in Division I college football players.     

Noncompatibility of power and endurance training among college baseball players

Exercise professionals seeking to develop evidence-based training programs rely on several training principles demonstrated through research and professional experience. In an effort to further research examining these principles, an investigation was designed and completed to evaluate the compatibility of cardiovascular endurance and neuromuscular power training. Sixteen Division-I collegiate baseball players were divided into two training groups with lower body power measured before and after their college playing season. The two groups differed in training in that one group performed moderate- to high-intense cardiovascular endurance training 3-4 days per week throughout the season, while the other group participated in speed/speed endurance training. A significant difference between groups (P < .05) was identified in the change in lower body power during the baseball season. During the season, the endurance training group decreased an average of 39.50 +/- 128.03 watts while the speed group improved an average of 210.63 +/- 168.96 watts. These data demonstrate that moderate- to high-intense cardiovascular endurance and neuromuscular power training do not appear to be compatible when performed simultaneously. For baseball players, athletes who rely heavily on power and speed, conventional baseball conditioning involving significant amounts of cardiovascular endurance training should be altered to include more speed/power interval training.     

Acute effects of heavy-load squats on consecutive squat jump performance

Postactivation potentiation (PAP) and complex training have generated interest within the strength and conditioning community in recent years, but much of the research to date has produced confounding results. The purpose of this study was to observe the acute effects of a heavy-load back squat [85% 1 repetition maximum (1RM)] condition on consecutive squat jump performance. Twelve in-season Division I male track-and-field athletes participated in two randomized testing conditions: a five-repetition back squat at 85% 1RM (BS) and a five-repetition squat jump (SJ). The BS condition consisted of seven consecutive squat jumps (BS-PRE), followed by five repetitions of the BS at 85% 1RM, followed by another set of seven consecutive squat jumps (BS-POST). The SJ condition was exactly the same as the BS condition except that five consecutive SJs replaced the five BSs, with 3 minutes' rest between each set. BS-PRE, BS-POST, SJ-PRE, and SJ-POST were analyzed and compared for mean and peak jump height, as well as mean and peak ground reaction force (GRF). The BS condition's mean and peak jump height and peak GRF increased 5.8% +/- 4.8%, 4.7% +/- 4.8%, and 4.6% +/- 7.4%, respectively, whereas the SJ condition's mean and peak jump height and peak GRF decreased 2.7% +/- 5.0%, 4.0% +/- 4.9%, and 1.3% +/- 7.5%, respectively. The results indicate that performing a heavy-load back squat before a set of consecutive SJs may enhance acute performance in average and peak jump height, as well as peak GRF.     

Acute effects of augmented eccentric loading on jump squat performance

The purpose of this study was to determine the acute effects of a spectrum of eccentric loads on force, velocity, and power during the concentric portion of maximal-effort jump squats utilizing a repeated measures design. Thirteen resistance-trained men (age = 22.8 +/- 2.9 years, weight = 87.1 +/- 11.8 kg, 163.5 +/- 28.6 kg squat 1 repetition maximum [1RM]; mean +/- SD), who routinely incorporated back squats into their training, participated as subjects in this investigation. Jump squat performance was assessed using 4 experimental conditions. The first of these conditions consisted of an isoinertial load equal to 30% of back squat 1RM. The remaining conditions consisted of jump squats with a concentric load of 30% 1RM, subsequent to the application of experimental augmented eccentric loading (AEL) conditions of 20, 50, and 80% of back squat 1RM, respectively. All subjects performed 2 sets of 1RM of maximum-effort jump squats with all experimental conditions in a counter-balanced sequence. Forty-eight hours after completing the first testing session, subjects repeated the experimental testing protocol to establish stability reliability. Peak performance values for the reliable variables of force, velocity, and power, as well as force and power values obtained at 20-ms intervals during the initial 400 ms of the concentric jump squat range of motion, showed no statistical difference (p > 0.05) across the experimental AEL loads. These results suggest that load-spectrum AEL prior to a 30% 1RM jump squat fails to acutely enhance force, velocity, and power.     

Effects of isoinertial or machine-based strength training on performance in tennis players

The objective of this study was to analyze the effects of two 8-week neuromuscular training (NMT) interventions on selected physical indicators in young tennis players. Twenty-four junior male tennis players were assigned to a machine-based (MG) (n = 8), flywheel (FG) (n = 8) or a control training group (CG) (n = 8). Tests at baseline, week 4 and 8 included: countermovement jump (CMJ); speed (S; 5, 10, 15 m); agility (right [AR] and left [AL]); serve velocity (SV) and medicine ball throws (MBT; overhead [O], forehand [FH], backhand [BH]). MG and FG attained large positive effects at week 4 in CMJ, S 10 m; AR, AL and MBT FH only in FG. Regarding inter- to post-test, MG achieved large positive effects in MBT O, FH and both groups in BH. Large negative effects appeared for FG in S 5 and 10 m and AR and AL. Both NMT interventions led to positive effects from baseline to week 4 measures in CMJ, S 5 m, 10 m and agility and at week 8 in MBT. Conducting the same NMT for a longer period of time did not lead to the same improvements and other negative effects in FG appeared. Results indicate that performing these interventions with little exercise variability or load management, especially after technical-tactical sessions, could interpose further beneficial outcomes and initial gains could be impaired.     

Comparison of land- and aquatic-based plyometric training on vertical jump performance

Plyometric training is a popular method by which athletes may increase power and explosiveness. However, plyometric training is considered a highly intense and potentially damaging activity particularly if practiced by the novice individual or if overdone. The purpose of this study was to compare vertical jump performance after land- and aquatic-based plyometric training. A convenience sample of 21 active, college-age (24 +/- 2.5 years) men were randomly assigned to 1 of 3 groups: group I, aquatic; group II, land; and group III, control. Training for the AQ and LN groups consisted of a 10-minute warm-up followed by 3 sets of 15 squat jumps, side hops, and knee-tuck jumps separated by 1-minute rests. The aquatic group performed the exercises in knee-level water adjusted to parallel the axis of the knee joint (+1 in.). The land group performed identical plyometric exercises on land. The control group engaged in no training. Participants trained twice a week for 6 weeks, and all training sessions were monitored. Pre- and post-test data were collected on maximum vertical jump height. A 2x3 analysis of variance with repeated measures was used to compare vertical jump height among the 3 groups. Results suggested that the aquatic- and land-based groups significantly (p < 0.05) outperformed the control group in the vertical jump. No significant difference was found in vertical jump performance between the aquatic- and land-based groups. It was concluded that aquatic training resulted in similar training effects as land-based training, with a possible reduction in stress due to the reduction of impact afforded by the buoyancy and resistance of the water upon landing.     

Effects of electromyostimulation training on muscle strength and power of elite rugby players

The present study investigated the influence of a 12-week electromyostimulation (EMS) training program performed by elite rugby players. Twenty-five rugby players participated in the study, 15 in an electrostimulated group and the remaining 10 in a control group. EMS was conducted on the knee extensor, plantar flexor, and gluteus muscles. During the first 6 weeks, training sessions were carried out 3 times a week and during the last 6 weeks, once a week. Isokinetic torque of the knee extensors was determined at different eccentric and concentric angular velocities ranging from -120 to 360 degrees .s(-1). Scrummaging and full squat strength, vertical jump height and sprint-running times were also evaluated. After the first 6 weeks of EMS, only the squat strength was significantly improved (+8.3 +/- 6.5%; p < 0.01). After the 12th week, the -120 degrees .s(-1) maximal eccentric, 120 and 240 degrees .s(-1) maximal concentric torque (p < 0.05), squat strength (+15.0 +/- 8.0%; p < 0.001), squat jump (+10.0 +/- 9.5%; p < 0.01), and drop jump from a 40-cm height (+6.6 +/- 6.1%; p < 0.05) were significantly improved. No significant change was observed for the control group. A 12-week EMS training program demonstrated beneficial effects on muscle strength and power in elite rugby players on particular tests. However, rugby skills such as scrummaging and sprinting were not enhanced.     

Relationships between isokinetic knee strength, single-sprint performance, and repeated-sprint ability in football players

Previous research has demonstrated that muscular strength of the knee extensors is related to the speed an athlete can produce during a single-sprint performance. Football players, as well as many other athletes on the field and the court, execute multiple sprints during the course of a match. The purpose of this study was to examine the relationships between leg strength, single-sprint speed, and repeated-sprint ability. Thirty-eight football players from 3 codes (soccer, rugby league, rugby union) completed a 12- x 20-m repeated-sprint protocol and were evaluated for peak isokinetic knee extension and flexion torque at 60 degrees .s(-1), 150 degrees .s(-1), and 240 degrees .s(-1). Although single-sprint performance correlated with peak extensor and flexor torque at all velocities, the strongest correlation was observed between relative knee extensor torque at 240 degrees .s(-1) and the initial acceleration phase (0-10 m) of the single-sprint performance (r = -0.714, p < 0.01). However, the data suggest that factors other than strength contribute to repeated-sprint ability. This finding provides new evidence in elucidating the relationship between strength and repeated-sprint performance.     

Effects of plyometric training and recovery on vertical jump performance and anaerobic power

We examined the effects of 2 plyometric training programs, equalized for training volume, followed by a 4-week recovery period of no plyometric training on anaerobic power and vertical jump performance. Physically active, college-aged men were randomly assigned to either a 4-week (n = 19, weight = 73.4 +/- 7.5 kg) or a 7-week (n = 19, weight = 80.1 +/- 12.5 kg) program. Vertical jump height, vertical jump power, and anaerobic power via the Margaria staircase test were measured pretraining (PRE), immediately posttraining (POST), and 4 weeks posttraining (POST-4). Vertical jump height decreased in the 4-week group PRE (67.8 +/- 7.9 cm) to POST (65.4 +/- 7.8 cm). Vertical jump height increased from PRE to POST-4 in 4-week (67.8 +/- 7.9 to 69.7 +/- 7.6 cm) and 7-week (64.6 +/- 6.2 to 67.2 +/- 7.6 cm) training programs. Vertical jump power decreased in the 4-week group from PRE (8,660.0 +/- 546.5 W) to POST (8,541.6 +/- 557.4 W) with no change in the 7-week group. Vertical jump power increased PRE to POST-4 in 4-week (8,660.0 +/- 546.5 W to 8,793.6 +/- 541.4 W) and 7-week (8,702.8 +/- 527.4 W to 8,931.5 +/- 537.6 W) training programs. Anaerobic power improved in the 7-week group from PRE (1,121.9 +/- 174.7 W) to POST (1,192.2 +/- 189.1 W) but not the 4-week group. Anaerobic power significantly improved PRE to POST-4 in both groups. There were no significant differences between the 2 training groups. Four-week and 7-week plyometric programs are equally effective for improving vertical jump height, vertical jump power, and anaerobic power when followed by a 4-week recovery period. However, a 4-week program may not be as effective as a 7-week program if the recovery period is not employed.